1. Technical Field
The present invention relates to a method for providing an Internet Protocol Television (IPTV) service, and more particularly to a method for reducing channel change time of an IPTV, and an IPTV service provision server for implementing the same, which increase network efficiency and reduce a delay time occurring during channel change.
2. Background Art
Recently, with the increasing development of communication and Internet technologies, a Triple Play Service (TPS) for simultaneously transmitting broadcast data, telephonic data, and other data via a single subscriber line has been introduced in the market. The TPS provides users with a variety of services in a package. The number of users who desire to use the TPS rapidly increases and the number of service provision enterprises also rapidly increases.
A representative example of TPS services is an IPTV service. The IPTV service provides users with broadcast services over the Internet network. Compared with conventional broadcast services (e.g., cable-, satellite-, or terrestrial-broadcast services), it uses the network resources more effectively.
In more detail, as shown in FIG. 1A, the conventional broadcast services must transmit data of all channels to users irrespective of requests of the users, resulting in the occurrence of wasted bandwidth. As shown in FIG. 1B, the IP multicast technology has been introduced to the IPTV service, and the IPTV service can solve the bandwidth problem due to insufficient subscriber lines. According to the IPTV service, data only for the channel requested by a user can be transmitted, and network resources can be effectively used.
However, the IPTV technology still has disadvantages. For example, if a user requests a new channel, a delay time (hereinafter referred to as a channel change delay) occurs until the user-selected channel is outputted to the user terminal.
The channel change delay is generally classified into a command-processing delay, a network delay, a Settop-box (STB) jitter buffer delay, and a decoding delay.
The command-processing delay is indicative of a delay time from a first time at which the user who desires to change a current channel to another channel selects a corresponding channel using a remote-controller to a second time consumed until the STB transmits the channel request message over a network. The network delay is indicative of a delay time consumed until a first packet of the requested channel is received. The STB jitter buffer delay is indicative of an initial buffering delay time for removing added jitters from the network. The decoding delay is indicative of a delay time caused by the decoding process of compressed video data. The decoding delay unavoidably occurs since the video data cannot be decoded without using intraframe (s).
The channel change delay makes users unable to immediately receive a desired video data at a desired time, thereby reducing efficiency of the IPTV services.
The information disclosed in this Background section is only for enhancement of understanding of the background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art that is already known to a person skilled in the art.